The present invention relates to a method for the removal of paint from wheel hubs, and to equipment for the implementation of such a method, intended as a manufacturing aid in the production of wheels, and in particular as part of the painting cycle in the manufacturing process.
In the art field of wheel manufacture, and more especially the production of wheels with superior functional and styling features, typically alloy wheels, the manufacturing process comprises the step of painting the wheel.
After being formed, whether pressed, pressure die cast or forged, the wheels are washed, dried and then painted, for example electrostatically.
To this end, the structure or body of the wheel is electrified with one polarity and the paint with the opposite polarity, so that the paint, which is applied in the dry state (powder or granules), will cling to the surfaces of the wheel by electrostatic attraction.
Thereafter, the paint undergoes heat treatment in ovens, the purpose being generally to bring about a process of polymerization or polycondensation by which it is hardened and rendered insoluble.
One of the problems betrayed by processes of this type is that particles of the paint find their way onto the substantially cylindrical surface defining the bore of the hub.
In effect, the hub is proportioned to match a given size of axle, and designed to accommodate the axle in its bore substantially without any clearance in the radial direction; in particular, the wheel may be fashioned with a pilot hole, that is, an annular profile by means of which the wheel is located on and aligned with the corresponding axle. This means that any imperfections exhibited by the surface of the hub destined to interact with the axle, however slight, are markedly significant when considering the high quality specifications to which wheels of the type in question are expected to respond.
It is the practice currently for traces of paint remaining on the hub to be removed manually by an operator who inserts a brush or similar implement into the bore and eliminates the unwanted particles by generating movement with the brush substantially in an axial direction relative to the wheel. Not only is a procedure of this type disadvantageous in that it requires manual labour, by reason of the painting cycle not being fully automated, but there is also the undesirable risk of paint being chipped away from the circular edge where the hub meets the exposed face of the wheel. This defacement leaves an area around the bore of the hub compassed by an irregular outline and exhibiting a colour or in any event a shade of colour dissimilar to the remainder of the wheel, which has a negative impact on the appearance of the wheel overall.
Accordingly, the object of the present invention is to provide a method and relative equipment for the removal of paint from wheel hubs, in particular the removal of electrostatically applied powders, such as will be devoid of the drawbacks mentioned above.